1. Field of the Invention
This invention relates in general to containers for handling, storing, and shipping charge sensitive electronic devices and, more particularly, to an improved container for handling, storing, and shipping semiconductor components requiring static charge protection.
2. Description of the Prior Art
It is well known that semiconductor devices, particularly metal-oxide-semiconductor devices are charge sensitive, that is, they can be readily damaged by static electric charge build-up during shipping, handling, and storage. Static electricity originates in a variety of different ways but most commonly by movement of persons or containers in which the devices have been placed so that when the devices or containers are touched, a charge is transferred from the person or the container to the device, resulting in critical damage to one or more of the sensitive components.
One conventional solution to this problem is to insert the terminals of the device in a piece of conductive foam for handling, shipping, and/or storage. The conductive foam maintains all of the terminals of the device at the same potential. Another solution is to use a conductive material as a part of the handling, storage, or shipping container itself. Typically, either the interior, or the exterior, or both interior and exterior surfaces of the container are coated with a conductive material, as for example, a carbon loaded ink or metal foil.
While such conductively coated containers have proved useful in suppressing static electricity damage, they suffer from a number of deficiencies of great practical significance. For example, those containers which are coated only on the inside provide electrical contact to the device themselves, but allow static electricity to build up on the outside of the container. Those which are coated only on the outside, while providing a conductive surface which is readily grounded, may allow static electricity to build up on the inside of the container. Additionally, the presence of a conductive coating on the outside of the container interferes with marking and labelling. For example, the typical carbon loaded conductive inks are black and it is more difficult and/or expensive to use the black conductive surface for marking, labelling, or advertising purposes. Those containers which are coated on both inside and outside are more expensive to produce because they require twice the amount of conductive ink plus additional labor, and they are still more difficult to mark and label than containers with uncoated outer surfaces. Further, most one-side coated containers can only be accessed by means of a flap which is an integral part of the package. Most two-sided coated containers used today are in the form of a tube or rail within which the electronic devices are stacked end-to-end.
Accordingly, it is an object of the present invention to provide an improved design for a static shielded container which permits greater flexibility in container configuration.
It is a further object of the present invention to provide an improved static shielded container which uses the minimum amount of conductive ink or coating.
It is an additional object of the present invention to provide an improved static shielded container which can be divided into two separable portions for easy loading and unloading, yet when reassembled provides a static electric shield completely surrounding the electronic components placed within.
It is a further object of the present invention to provide an improved static shielded container in which the outside surface of the bottom is conductive so that the container shield as a whole is readily brought to earth potential.
It is a still further object of the present invention to provide an improved static shielded container in which the top and/or sides are free of conductive material so as to be more adaptable to printing, marking, and labelling.